Chemical synthesis

Pure acidic compunds that are solid include; citric and tartaric, that are liquid include; sulphuric, nitric and ethanoic, that are gases include; hydrogen chloride

When we react acids and alkalis this is called chemical synthesis. The stages that are envolved with this are:

Choosing the reactant or the series of reactions that make the required product

Carrying out the rick assessment

Working out the quantaties of reactants to use

Carrying out the reaction with suitable appratus in the right conditions (such as temperature, concentration

Seperating the product from the reactant mixture (such as filtering)

Purifying the product (such as evaporation, crystallination, drying in an oven or in a desiccator) It is important the product is pure because the smallest impurty could cause harm eg. in a phamaceutical drug. This can be done through titrations

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Endothermic and Exothermic reactions

In a reaction bonds are broken releasing energy and bonds are formed absorbing energy.

in a endothermic reaction more energy is envolded to form bonds than to break them so energy is absorbed from the surroundings.

Where as, in an exothermic reaction more energy is needed to break the bonds than to form them so energy is released into the environment (usually as heat energy)

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Calculating percentage yeild

Percentage yield = actual yield∕predicted yield × 100

For example, if the predicted yield is 20 g but the actual yield is 15 g:

Percentage yield = 15∕20 × 100 = 75%

Why the percentage yield of a product may be less than 100%:

Filtering

Evaporating

Transferring liquids

Not all reactants react to make product

Industrial processes want a high percentage yeild because it reduces the waste of the reactants and the cost of the process

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Titrations

Measure you acid into a burette using a pipette. Measure your sodium hyrdoxide into a conical flask and add universal indicator. Place the conicle flask on a white tile

Whilst swirling add the acid to the hydroxide faster at the beginning. Stopping when the colour of the indicator changes to record your results.

Repeat your titrations, once you now the rough numbers add your acid drop by drop. These rough numbers can now be discarded.